Select the correct answer to the questions from the given options. (Do not copy the questions, write the correct answer only.)
The heart sound ‘Dup’ is produced when:
Topic: Heart sounds
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Pick an option and check your answer. The full worked answer is below either way.
Answer
(c) Semilunar valves close.
The two heart sounds are made by valves CLOSING, never opening — that single fact eliminates options (a) and (d) at once.
"LUBB" — the first sound, longer and duller. Made by the ATRIOVENTRICULAR valves (tricuspid and bicuspid) closing at the start of ventricular SYSTOLE. "DUP" — the second sound, short and sharp. Made by the SEMILUNAR valves closing at the start of ventricular DIASTOLE.
A way to remember the order: the sounds come in the order LUBB-DUP, and the valves close in the same order the blood travels — first the ones between atrium and ventricle, then the ones at the exits into the arteries.
The sounds matter medically: a "murmur" means a valve is leaking, so a doctor listening to the chest is checking the valves.
Semilunar valves close.